Method and apparatus for producing corrugated board



Sept. 23, 1969 F. H L 3,468,734

METHOD AND APPARATUS FOR PRODUCING CORRUGATED BOARD Filed Feb. 7. 1966 INVENI'U/( iziferf 5/4105 United States Patent .0

3,468,734 METHOD AND APPARATUS FOR PRODUCING CORRUGATED BOARD Albert F. Shields, Forest Hills, N.Y., assignor to S & S

Corrugated Paper Machinery Company, Inc., Brooklyn,

N .Y., a corporation of New York Filed Feb. 7, 1966, Ser. No. 525,598 Int. Cl. B31f 1/20 US. Cl. 156-210 Claims ABSTRACT OF THE DISCLOSURE Double face board is produced with a plaited corrugated layer by longitudinally compressing the plaited medium and thereafter longitudinally drawing out the folds by utilizing a suction conveyor to accurately control flute height and pitch while an underfed liner is applied. This forms single face board which is moved by another conveyor past a station where the second liner is applied from above.

This invention relates to corrugated board in general and more particularly relates to board of this type in which the corrugated layer is of a profile having sharp flute tips.

In order to produce single or double faced corrugated board at an economical price, it is necessary that such board be formed by a high speed continuous flow process. In order to obtain runability of the corrugating medium through the corrugating rolls the flutes of the corrugated layer are limited in form and must have rounded tips. This results in a considerable waste of paper in that the strongest truss formation of combined board with greatest economy of paper use comes about when the flutes are provided with straight sides and sharp tips. In other words, in order to obtain the strongest corrugated board for the amount of paper used the corrugated layer should be plaited.

While the prior art has been aware of the foregoing, no reliable high speed continuous process has been provided for the production of corrugated board having a plaited corrugated layer. This is believed to be the result of the difiiculty in maintaining proper height and pitch of the corrugated layer especially during the application of the first liner.

The instant invention provides a novel process and a novel apparatus for producing so-called plaited corrugated board on a high speed continuous basis by plaiting the corrugating medium, compressing the plaited medium and thereafter drawing out the folds longitudinally in a controlled manner in order to obtain flute heights and pitches of desired value. This drawing out of the compressed plaited medium is done, while additional folds are being compressed, by suction belts set with an accurate gap to give proper flute height with the suction belts being driven at a speed calculated to produce proper flute pitch for the flute height chosen. Once proper flute height and pitch are obtained, such height and pitch may readily be maintained while single-face liner is applied. After formation of single-face board, the single-face liner is engaged by additional suction belt means to permit bonding of a second liner to produce the doubleface board.

Accordingly, a primary object of the instant invention is to provide a novel process and apparatus for the continuous high speed production of corrugated board having a plaited corrugated layer.

Another object is to provide a continuous high speed process for the production of corrugated board that does not require the formation of flutes in heated corrugating rolls.

3,468,734 Patented Sept. 23, 1969 ice A further object is to provide a process and apparatus of this type in which compressed plaited material is drawn out longitudinally in a controlled manner by means of a pair of suction belts set with an accurate gap therebetween.

These as well as other objects of this invention will become readily apparent after reading the following description of the accompanying drawing wherein FIG- URES 1A and 1B combined (by placing FIGURE 113 at the right of FIGURE 1A) schematically illustrate novel apparatus constructed in accordance with the teachings of the instant invention.

Now referring to the figure. Apparatus 10 produces corrugated board 11 having corrugated layer 12 with sharp profile flute tips by combining corrugating medium web 13 and liner webs 14, 15. Webs 13, 14, 15 are typically kraft paper supplied from rolls 16, 17, 18, respectively. Web 13, as it leaves roll 16, moves in a forward direction (indicated by arrow A) through apparatus 10 in a generally horizontal path parallel to the longitudinal axis of Web 13.

Initially web 13 passes between cooperating crimping rolls 20, 21 which nick Web 13 along uniformly spaced transverse lines. As the crimped web moves forward of rolls 20, 21 it enters between spaced guide fingers 22, 23 which cooperate to define a generally horizontal accumulating passage wherein the crimped web is longitudinally compressed by virtue of the fact that at the beginning of a run the plaits are made to fill the length between the guides 22, 23. Then leading edge of the compressed plaited Web is fed between suction belts 24 and 25 whose forward speed is accurately set in relation to the gap therebetween (Le. board caliper) to carry off the same amount of paper as is produced by the crimping rolls. The compressed plaited web 26 is drawn out in a forward direction from between guide fingers 22, 23 by the confronting horizontal flights of conveyor belts 24, 25. Belts 24, 25 are perforated with the confronting horizontal flights thereof passing over the partially opened sides of suction chambers 28, 29, respectively. Spacing between the confronting horizontal flights of belts 24, 25 is maintained by having these flights in intimate contact with grate-like means (not shown) forming the lower and upper boundary walls for chambers 28, 29, respectively. Although not illustrated, the inner surfaces of belts 24, 25 are notched along both edges with the notch formations being engaged by drive sprockets keyed to shafts 30, 31.

By maintaining an accurate speed relationship between suction conveyor belts 24, 25 and crimping rolls 20, 21 and also by maintaining an accurate spacing between the opposed horizontal flights of belts 24, 25 the compressed crimped web 26 is drawn out in an accurately controlled manner thereby obtaining desired flute height and pitch.

Suction applied from chamber 28 acts to draw the upper flute tips against belt 24 while suction applied through chamber 29 acts to draw the lower flute tips against belt 25. While the rear ends of belts 24, 25 are positioned at the same point along the feed path of Web 13 belt 25 terminates at a point considerably to the rear of the termination for belt 24. By the time web 13 reaches the forward end of belt 25 the flutes have a pitch and height corresponding to that selected for corrugated layer 12 of the finished double-faced board 11. In the space between the forward end of belt 25 and the rear end of belt 41 for applying bottom liner web 14, web 12 is supported by suction applied through belt 24. In the region between belts 25 and 41 the periphery of glue roll 42 on shaft 42' engages the lower flutes of corrugated web 12 applying glue thereto and shortly thereafter, at a time before this glue sets, web 12 passes over the upper flight of belt 41 with web 14 entering between web 12 and belt 41. The upper flight of belt 41 is accurately guided in a horizon- 3 tal path by grate-like means (not shown) forming the upper wall of suction chamber 43.

The forward portion of belt 24 overlaps the rear portion of belt 41 and in this overlapping region belt 24 provides the requisite pressure for maintaining the glue covered lowered flute tips in intimate contact with web 14 to assure satisfactory bonding. By the time single-face board 44 passes the forward end of belt 24 the glue applied by wheel 42 has set sufliciently to assure that corrugated web 12 is fixed in position with respect to liner 14 and the latter is moved forward by belt 41 being held in place by suction applied through chamber 43.

As single-face board 44 moves forward past belt 24 the upper flute tips of Web 12 moves below and contacts the periphery of glue roll 46. Thereafter, board 44 passes below guide wheel 47 where top liner web engages the upper glue covered flute tips. While the glue on the upper flute tips is setting spring pressure biased plate 48, which confronts the forward portion of the upper flight for belt 41, engages top liner 15 applying a downward pressure thereto to assure good bonding to corrugated web 12.

It is noted that the flutes of corrugated web 12 have straight sides and have pointed tips, rather than rounded tips. This results in double-face board 11 having greater strength for the amount of paper used as compared to corrugated board of equal thickness and paper caliber wherein the corrugation flutes are rounded.

Thus, this invention provides a novel means and a novel process for the continuous high speed production of corrugated board in which the corrugated layer is provided with flutes having a sharp tipped profile. It is noted that no attempt has been made to show details of construction for the various mechanical elements or the driving means therefor since to one skilled in the art the schematic representations of the drawing and the foregoing description constitute a full and complete disclosure of the instant invention.

Although there has been described a preferred embodiment of this novel invention, many variations and modifications will now be apparent to those skilled in the art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appending claims.

The embodiments of the invention in which an exclusive privilege or property is claimed are defined as follows:

1. A method for producing multilayer board including a layer having flutes with pointed tips, said method including the steps of crimping a moving web of sheet material to produce undulations in said web in the form of flutes extending transverse to the direction of travel, compressing the crimped web in the direction of web travel to a point where flute angle is less than the selected flute angle of multilayer board being produced, drawing the compressed crimped web out at a controlled rate to increase flute angle to a selected angle, and thereafter bonding a flat web of sheet material to flute tips at one side of said crimped web while said crimped web is in motion.

2. A method as set forth in claim 1 in which suction is applied to said flute tips to hold said flutes at said se lected angle.

3. A method as set forth in claim '2 in which said suction is applied to flute tips on both sides of said crimped web; said suction directed to draw flute tips on the other side of said crimped web away from said one side and also directed to draw flute tips on said one side away from said other side.

4. Apparatus for producing multilayer board including a layer having flutes with pointed tips; said apparatus including continuously operable first means for crimping a web of sheet material to produce undulations in such web in the form of flutes extending transverse to the direction of web travel; a second means for receiving crimped web produced by said first means and compressing such crimped web in the direction of web travel to a point where flute angle is less than the selected flute angle of multilayer board being produced; third means for receiving crimped web from said second means and drawing the compressed crimped web out at a controlled rate to increase flute angle to a selected angle; and additional means for thereafter bonding a flat web of sheet material to flute tips at one side of said crimped Web While said crimped web is in motion.

5. Apparatus as set forth in claim 4 in which the third means includes conveyor belt means having opposed spaced moving flights between which such compressed crimped web is drawn out, and suction applying means acting through said belt means to bring flute tips of said crimped web into engagement with said opposed spaced moving flights.

6. Apparatus as set forth in claim 4 in which said second means includes an accumulating passage wherein said crimped web is compressed, with drawing out of the compressed web at a controlled rate taking place through one end of the accumulating passage while crimped sheet material enters said accumulating passage at the other end thereof.

7. Apparatus as set forth in claim 4 further including further means for bonding another fiat web of sheet material to flute tips at the other side of said crimped Web while said crimped web is in motion.

8. Apparatus as set forth in claim 7 in which the third means includes conveyor belt means having opposed spaced moving flights between which such compressed crimped web is drawn out, and suction applying means acting through said belt means to bring flute tips of said crimped web into engagement with said opposed spaced moving flights.

9. Apparatus as set forth in claim 8 in which the crimped web is maintained in motion during bonding of said flat web by a suction holding force generated by said suction applying means and acting through a flight of said conveyor belt means to draw the flute tips at the other side of said crimped web into engagement with said belt means.

10. Apparatus as set forth in claim 9 in which said flat web is positioned on said one side of said crimped web, and there is a suction conveyor means engaging said flat web and controlling movement thereof during said bonding of said another flat web.

References Cited UNITED STATES PATENTS 2,068,155 1/1937 Swift 156-473 2,141,235 12/1938 Angeletti 156-474 XR 2,166,749 7/1939 Burrill 156 471 2,788,841 4/1957 Hockett 156-588 1,924,472 8/1933 Thomson 156197 XR 2,982,333 5/1961 Little 16l-l37 3,266,690 8/1966 Goettsch 156-471 XR EARL M. BERGERT, Primary Examiner H. F. EPSTEIN, Assistant Examiner US. Cl. X.R. 156-471 

